近来,化学防治锈病的方法已越益得到注视。而决定化学处理有否成效的一个因素就是进行化处的时期。为此便提出了病害予测和化学措施的经济效果问题。因为大规模的化学处理是需要耗费大量的劳力和资材,因此有科学根据地减缩化学处理的数量,既能节约经费又能减轻因用杀菌剂所造成污染环境的危险性。客观实践对予测的要求是很严格的。必须弄清,需用杀菌剂进行处理范围的大小以 Recently, methods of chemical prevention of rust have become increasingly sought after. One of the factors that determine the effectiveness of chemical treatment is the period of change. To this end, the economic effects of disease prediction and chemical measures are put forward. Because large-scale chemical treatment requires a lot of labor and materials, scientifically reducing the amount of chemical treatment can save money and reduce the risk of environmental pollution caused by fungicides. Objective requirements of the practice of the test is very strict. Must be clear, the need to use disinfectant to deal with the size of the range